Today, many video streams arrive at different devices when they are compressed as MPEG streams. Processing them in the MPEG domain is cheaper and much more cost-effective than decoding the streams, processing the baseband video streams and then encoding the result. MPEG streams include multiple frames that are arranged in group of pictures. A group of pictures (GOP) can start by an independently decodable frame (such as an I frame) that is followed by multiple dependently-decodable frames (such as B frames and P frames). In various applications a mosaic image is required. This can include, for example, Electronic Program Guides, video conferencing, picture in picture applications and the like. For example, a user can receive a mosaic image that includes a large representation of one video stream and multiple thumbnails of the other video streams. In this case, the associated audio stream is the one originally associated with the large-representation stream.
There is a growing need to generate mosaic images with relatively simple and low cost systems.